基于对数比变换和分形模型的地球化学异常识别与提取OA

The identification of weak and gradual anomalies in the coverage area and the delineation of target areas are the difficulties in mineral exploration.More than 50%of the Gejiu tin polymetallic deposit area in Yunnan is covered by Late Triassic Gejiu Formation limestone,which is a typical old mine and requires a new round of explora-tion work.This article takes the Gejiu tin polymetallic deposit as the research object,and uses 1∶200 000 water sedi-ment data to perform logarithmic ratio transformation,factor analysis,S-A analysis,and target area delineation.The results indicate that the additive logarithmic ratio transformation enhances the geological interpretability of factor analysis,and the element combinations of factors F1 and F2 represent the Sn mineralization characteristics of acidic magmatic hydrothermal high medium low temperature superposition and the Cu mineralization characteristics of basic magmatic systems,respectively;The abnormal area analyzed by S-A is highly consistent with the Gejiu east and west deposit,confirming that the S-A fractal method can effectively eliminate the"closure effect"and improve the efficiency of anomaly identification in the coverage area;Four potential target areas were identified in the unexplored anomaly zone,providing the scientific basis for subsequent exploration of tin resources.